1. Field of Invention
The present invention relates, generally, to automotive engine systems and, more specifically, to a valvetrain assembly for engines.
2. Description of the Related Art
Conventional engine valvetrain systems known in the art typically include one or more camshafts in rotational communication with a crankshaft supported in a block, one or more intake and exhaust valves supported in a cylinder head for regulating the flow of engine gasses, and one or more rocker arms for translating radial movement from the camshaft to linear movement of the valves. To that end, rocker arms are typically rotatably supported to a shaft which, in turn, is operatively attached to the cylinder head, thereby allowing the rocker arm to pivot about the shaft in response to rotation of the camshaft. The rocker arm typically includes a pad for engaging the valve, and a socket for engaging an intermediate member in communication with the camshaft. As the camshaft rotates, the intermediate member translates movement from the camshaft to the socket of the rocker arm, which pivots the rocker arm such that the pad subsequently translates force to the valve so as to open it. Thus, to effect rotation about the shaft and maintain proper engagement of the pad to the valve, and the socket to the intermediate member, the configuration of the rocker arm can be complicated in terms of geometry and packaging, particularly where the engine application necessitates a narrow-width cylinder head.
Because of the number of different engine types known in the art, the orientation and configuration of valvetrain systems typically varies with the engine application. One well known engine application known in the art, commonly referred to as a “cam-in-block” or “pushrod” engine, utilizes a valvetrain system that includes multiple rocker arms. As the convention suggests, in this application, the camshaft is rotatably supported in the engine block and the valves are supported above the camshaft. The intermediate member is typically a pushrod that engages the socket of the rocker arm at one end, and a hydraulic lash adjuster in communication with the camshaft at another end. In some applications, oil is translated along the intermediate member, such as through the pushrod, along a path going either to or from the rocker arm so as to lubricate and ensure proper rotation about the shaft.
Each of the components of an engine valvetrain system of the type described above must cooperate to effectively translate movement from the camshaft so as to operate the valves. In addition, each of the components must be designed not only to facilitate improved performance and efficiency, but also so as to reduce the cost and complexity of manufacturing and assembling the valvetrain system. While rocker arm assemblies and engine valvetrain systems known in the related art have generally performed well for their intended purpose, there remains a need in the art for a rocker arm assembly that has superior operational characteristics, and, at the same time, reduces the cost and complexity of manufacturing the components of the system, as well as the overall packaging size of the engine.